It gets to be even more of a problem if we consider free will. As with us observing our own consciousness, we observe ourselves making decisions, and we observe our fellow people appearing to make choices. Yet many go so far as to deny the existence of free will because it violates certain notions of causation. Tolstoy thought it an illusion soon to be thrown on the scrap heap of intellectual history along with the geo-centric universe.

Dostoevsky's Underground man had an interesting take:

https://www.gutenberg.org/files/600/600-h/600-h.htm#chap08

Yet we cannot conceive of ourselves as fully human without free will. Slavery is dehumanizing precisely because it deprives the slave of choice.